5.1 - Lesions of the Motor System Flashcards Preview

ESA 5 - Nervous System > 5.1 - Lesions of the Motor System > Flashcards

Flashcards in 5.1 - Lesions of the Motor System Deck (19)
Loading flashcards...

Define a positive and negative sign of a neurological lesion?

Negative sign - Loss of function or capacity

Positive sign - Emergence of a feature e.g. tremor


Label the cerebellar functional divisions


What is the general function of each functional zone of the cerebellum?

vestibulocerebellum - Balance and ocular reflexes

spinocerebellum - Involved in Error correction

Cerebrocerebellum - Movement planning and motor learning, esp visually guided movements and coordination of muscle activation


Label the arteries that supply the cerebellum. From which arteries are these derived?


Which veins drain the cerebellum and where do these veins then drain into?

Superior and inferior cerebellar veins

drain into transverse and sigmoid sinuses


Give 3 common causes of cerebellar dysfunction


Cerebrovascular disease

Genetic e.g. Friedrichs ataxia


Give 4 possible signs of damage to the cerebrocerebellum and spinocerebellum

ataxia, dysarthria and scanning speech, hypotonia, dysdiadochokinesia, inability to learn new movements


Give 2 signs of damage to the vestibulocerebellum

abnormal gait with a wide stance, and loss of balance


Label the anatomical divisions of the cerebellum


describe the embryonic development which leads to the cerebellum

Neural tube forms prosencephalon, mesencephalon, and rhombencephalon

Rhombencephalon splits into metencephalon (superior) and myelencephalon (inferior) - Metencephalon forms cerebellum


Give 6 signs of a UMN lesion

Hyperreflexia, hypertonia, spastic paralysis, babinski sign, myoclonus, choreas


What is a positive and negative sign of babinski?

Positive - abduction of toes and dorsiflexion of big toe

Negative - flexion of toes


What does a positive babinski mean?

UMN lesion in the corticospinal tract


Give 4 signs of LMN lesions

flaccid paralysis, denervation atrophy, areflexia / atonia, fasciculations


Explain why fasciculations occur in LMN lesions

deinnervation of muscles means nACHRs have become hypersensitive to any neurotransmitter substances or molecules even vaguely similar to ACh such as those found in the blood. Results in slight muscle contractions


In the case of LMN lesions, when is the damage irreversible?

If the cell body is damaged, no regeneration can take place.


How is  micturition affected by a LMN lesion in S2-S4?

Overflow incontinence - autonomous bladder


Describe what spinal shock is. Why does it occur?

When descending tracts damaged, there is a recovery period of 4 - 6 weeks where there is flaccid paralysis and areflexia in the affected limbs. This is then replaced with spasticity and hyperactive deep reflexes.

It occurs because the loss of reflexes is due to loss of motor influences exerted by descending fibres. As these fibres degenerate the intact connections in the reflex circuits become dominant and show themselves as upper motor neurone signs